Can CT determine the site of traumatic osteochondral defects in the paediatric knee?

Currently the ability of pre-operative CT imaging to determine the origin of traumatic osteochondral lesions (OCL) in the knee in children is yet to be established. The surgical approach to the knee will to some extent be determined by the origin of the lesion. It is important to directly determine the site of the lesion from pre-operative scanning both to facilitate surgery, to have a better cosmetic result for the patient and have a quicker rehabilitation period. In a tertiary referral centre, from May 2004 to April 2005, eight patients were diagnosed as having an OCL. The initial reporting was done by either a senior registrar or consultant paediatric radiologist. Those children that had an OCL underwent an arthroscopy or definitive open surgery. The exact site of the lesion was then determined and recorded in the operative notes. All the original pre-operative CT scans were given to a senior paediatric radiologist. The consultant on this occasion had no access to operative findings, or original CT reports. CTs reported by the paediatric radiology department are only able to correctly identify the site of origin of the OCL 50% of the time. Recent MR scanning techniques have improved the visualization of OCL. We authors therefore feel that in the future MRI should be used to assess the paediatric knee when an acute OCL is suspected.

The use and availability of thyroid shields in orthopaedic theatres: a telephone questionnaire of English hospitals.

There are no published guidelines issued for the use of thyroid shields by either the Royal College of Radiologists or the British Orthopaedic Association. It has previously been demonstrated that a thyroid shield should be worn during fluoroscopic screening using a portable image intensifier. Scrub staff not wearing a thyroid shield are currently being exposed to ionising radiation on a regular basis, with potentially harmful effects. Of the 210 hospitals in England with orthopaedic departments, 179 were telephoned and the use and availability of thyroid shields was asked. The results demonstrated that 98 orthopaedic theatres had sufficient numbers of thyroid shields available. Of these 98 orthopaedic theatres, thyroid shields were routinely used in only 28 theatres during fluoroscopic screening on a regular basis. It is the authors' recommendation that thyroid shields should be worn during orthopaedic procedures involving the use of an image intensifier.

The influence of the posterior cruciate ligament in the maintenance of joint line in primary total knee arthroplasty: a radiologic study.

The aim of this study was to compare 2 total knee arthroplasty (TKA) designs radiologically to determine if a posterior cruciate ligament (PCL)-substituting design led to a built-in error of elevation of the joint line postoperatively. The restoration of the true joint line is a goal in primary TKA, although its effect on outcome has not been established fully. A total of 47 patients had 56 TKAs performed by 2 surgeons using either the Howmedica Kinemax Plus (Rutherford, NJ) PCL-retaining or PCL-substituting TKAs. The patients were randomized to receive one of these designs, and the height of the joint line was assessed radiographically preoperatively and postoperatively. The joint line position preoperatively averaged 2.2 cm from the tibial tuberosity and postoperatively averaged 2.4 cm (PCL substituting) and 2.5 cm (PCL sparing). No difference in the thickness of the polyethylene insert used was seen with either design. The theoretical elevation of the joint line that occurs with the sacrifice of the PCL was not found to occur radiologically.

Does diplopia persist after blow-out fractures of the orbital floor in children?

Blow-out fractures of the orbital floor are comparatively rare in children, particularly those less than 8 years old. Published reports have suggested that the long-term outcome in children is worse than that in adults with similar injuries. In this study, we examine this question in the light of data from 45 children from Birmingham and Glasgow who were divided into three age ranges: 0-9 years (n = 9), 10-12 years (n = 11) and 13-15 years (n = 25). Fourteen were treated conservatively and 31 were treated surgically. The 0-9-year-old group were more likely to have small- or medium-sized defects in the anterior part of the orbital floor, which were of a linear 'trapdoor' type. The 13-15-year-olds tended to have larger 'open-door' defects. More than half the 0-9-year-olds had persistent diplopia compared with just under a third of the two other age groups. This diplopia took twice as long to resolve in the younger group compared with the other two groups. Our results confirm the view that younger patients have more persistent problems than adults after blow-out fractures of the orbital floor.

The compressible silicone rubber prosthesis in temporomandibular joint disease.

An alternative technique for temporomandibular joint arthroplasty is described, in which the mandibular condyle is replaced by a soft compressible silicone rubber prosthesis. A modified Nicolle-Calnan metacarpo-phalangeal joint prosthesis was used to reconstruct 31 joints in 24 patients. Results suggest that in those patients where there has been no loss of the prosthesis, function continues to be markedly improved when compared with the pre-operative condition. Painful symptoms were relieved in cases of specific joint pathology but the technique was of little value in the management of dysfunctional pain when radiographic evidence of joint pathology was absent. A specifically designed TMJ prosthesis of this type may be a useful addition to the surgeon's armamentarium.

Spontaneous fracture of an atrophic endentulous mandible treated without fixation.

The positive clinical decision to treat a spontaneously fractured edentulous mandible passively depends on a careful evaluation of local and general factors pertaining. These include: (1) Preferably simple fractures with minimal displacement and an intact periosteal sheath. (2) Elderly and infirm patients and others in whom surgery is contra-indicated. (3) Case in which discomfort and inconvenience with fixation is likely to be worse than without, bearing in mind that fixation does not guarantee firm bony union and that many patients wear dentures and masticate successfully in the presence of complete failure of fragments to unite. It must be stressed that it is not suggested that this line of treatment be followed routinely, but that is is valid in certain selected cases.